Heatwaves and Heart Disease: What Patients Should Know

Very hot days are not just uncomfortable. For people with heart disease, extreme heat can become a serious health concern.

When the weather is very hot, the body tries to cool itself down. Blood vessels widen, we sweat more, and we lose water and minerals. As a result, the heart has to work harder to keep blood circulating throughout the body.

For a healthy person, this extra effort may go unnoticed. However, for people with high blood pressure, heart failure, coronary artery disease, a previous heart attack, or heart rhythm disorders, hot weather can make symptoms worse.

How does heat affect the heart?

During a heatwave, the body loses fluids through sweating. If you do not drink enough or lose too much fluid, dehydration may occur.

Dehydration can lead to:

• low blood pressure;
• dizziness or weakness;
• a faster heartbeat;
• palpitations;
• increased fatigue;
• worsening shortness of breath in people with heart disease.

In addition, some heart medications may affect how the body responds to heat. For example, diuretics increase fluid loss, and some blood pressure medications may cause blood pressure to drop more than usual during very hot weather.

That is why people with heart disease should pay extra attention to how they feel during heatwaves.

Who is at higher risk?

Extreme heat is more dangerous for:

• people with high blood pressure;
• patients with heart failure;
• people who have had a heart attack;
• patients with angina;
• people with atrial fibrillation or other heart rhythm disorders;
• older adults;
• patients taking diuretics;
• people performing physical activity in hot weather.

Which symptoms should never be ignored?

Seek medical attention immediately if you experience:

• chest pain, pressure, or tightness;
• significant shortness of breath;
• fainting or feeling as if you may faint;
• persistent palpitations;
• confusion;
• severe weakness;
• cold sweats;
• a sudden worsening of your overall condition.

These symptoms may indicate a serious heart problem and should not simply be blamed on the heat.

How can you protect yourself?

1. Avoid going outside during the hottest hours

Try to stay indoors between 11:00 a.m. and 6:00 p.m., especially on extremely hot days.

If you must go outside, stay in the shade, wear lightweight, light-colored clothing, and protect your head with a hat.

2. Stay hydrated, but be careful if you have heart failure

Drink fluids regularly during hot weather. Do not wait until you feel very thirsty.

However, if you have heart failure and your doctor has advised you to limit your fluid intake, do not increase the amount of water you drink on your own. Ask your doctor how much fluid is appropriate for you during hot weather.

General advice such as "drink as much water as possible" is not suitable for everyone.

3. Avoid strenuous physical activity

Physical exertion in hot weather puts additional strain on the heart. Avoid fast walking, heavy lifting, gardening, or sports during the hottest part of the day.

If you want to exercise, choose the early morning or evening when temperatures are lower.

4. Check your blood pressure

Blood pressure may be lower than usual during hot weather, especially if you take medication for high blood pressure.

If you feel dizzy, weak, have blurred vision, or feel like you might faint, check your blood pressure. If it is unusually low or your symptoms continue, contact your doctor.

5. Do not stop taking your medications without medical advice

Even if you feel weaker than usual or notice lower blood pressure readings, do not stop your medication on your own.

Sometimes treatment adjustments are necessary, but only your doctor should make those decisions.

6. Stay in cool places

Whenever possible, spend time in cool, well-ventilated rooms. Avoid prolonged exposure to direct sunlight, overheated cars, or poorly ventilated spaces.

Cool showers, lightweight clothing, and lighter meals may also help your body cope with the heat.

When should you see a cardiologist?

A cardiology consultation is recommended if:

• you tolerate hot weather worse than before;
• you develop new or more frequent palpitations;
• you become tired more easily;
• you experience shortness of breath;
• your blood pressure becomes unusually high or low;
• you have episodes of dizziness or fainting;
• you have heart disease and are unsure how to manage it during hot weather.

Sometimes a simple evaluation is enough to determine whether your symptoms are caused by the heat or by a heart condition that requires treatment.

Conclusion

Extreme heat can place additional stress on the heart, especially in people with cardiovascular disease. Proper hydration, avoiding excessive heat, monitoring your blood pressure, and taking your medications as prescribed are simple but important steps to reduce the risk of complications.

If you have high blood pressure, heart failure, atrial fibrillation, coronary artery disease, or have previously had a heart attack, take extra care during periods of extreme heat.

If you develop chest pain, severe shortness of breath, persistent palpitations, fainting, or profound weakness, seek medical attention without delay.